Pen injectors are known in the prior art and typically include a dose-adjustment mechanism for setting a dose, for example of insulin, and a pen needle for insertion into a patient to allow proper drug administration. The pen needle should be single-use and replaced with each administered dose.
The pen needle includes a distal end formed for insertion into a patient and a proximal end for insertion into a drug vial or cartridge located inside the pen injector. The proximal end of the needle will typically have to pierce a septum or stopper provided on the end of the vial or cartridge to access the drug. Devices have been developed in the prior art to shield the distal, or patient, end of the needle after use; particularly, to prevent an inadvertent “needle stick” after use. Even with the distal end being shielded, the proximal, or non-patient end, is exposed.